Metal trap for hammer mills or the like

ABSTRACT

A trap for foreign objects, such as tramp metal, introduced into a hammer mill or the like having impact hammers supported within a mill cavity for rotational movement about a generally horizontal axis. The trap is characterized as being supported exteriorally of the mill cavity on a mill cavity access door and as being arranged in communication with the mill cavity through an access door defined opening disposed adjacent an inlet opening of the cavity. The trap is formed with a receiving chamber, a smoothly curved top wall plate extending from an upper edge of the trap opening for directing objects propelled therethrough by the impact hammers downwardly into the receiving chamber, a retaining plate extending from a lower edge of the trap opening in overlying relation to the receiving chamber for retaining objects collected therein, and a door bounding the receiving chamber for affording access to the collected objects.

[15] 3,677,478 July 18, 1972 United States Patent Schutte Primary Examiner-Robert L. Spruill Anomey-Bean & Bean [54] METAL TRAP FOR HAMMER MILLS OR THE LIKE [72] lnventor:

[57] ABSTRACT A trap for foreign objects, such as tramp metal, introduced into a Harry D. Schutte, Williamsville, NY.

Schulte Pulverlmer Co., Inc., Bufi'alo, N.Y.

hammer mill or the like having impact hammers supported within a mill cavity for rotational movement about a generally horizontal axis. The trap is characterized as being supported exteriorally of the mill cavity on a mill cavity access 0 7 9 l 9 8. w v, 01. N9 e an a M w A FA 1]] 32 722 door and as being arranged in communication with the mill cavity through an access door defined opening disposed adjacent an inlet opening of the cavity. The trap is formed with a receiving chamber, a smoothly curved top wall plate extending from an upper edge of the trap opening for directing ob jects propelled therethrough by the impact hammers downwardly into the receiving chamber, a retaining plate extending from a lower edge of the trap opening in overlying relation to the receiving chamber for retaining objects collected therein, and a door bounding the receiving chamber for affording access to the collected objects.

5Claims,3DrawingFigures lt J Isl I t Patented July 18, 1972 2 Shets-Sheet 1 INVENTOR. HflRRYO. SCHUTTE GLMGM A TTOPNEYS Patented July 18, 1972 3,677,478

2 Sheet-Sheet Z I NVEJN'TOR HIQRRYD. SCHUT TE ATTORNEYS METAL TRAP FORIIAMMER MILLS OR THE LIKE BACKGROUND OF THE INVENTION l-leretofore, traps of varying designs have been employed for the purpose of removing hard objects such as tramp metal, stones or the like from mills constructed to shred or triturate soft solids or semi-solids. Prior tramp metal traps, insofar as I am aware, have suffered from one or more drawbacks. The most serious of these drawbacks is the failure of these traps to insure that all of the foreign objects are removed from the mill cavity and that once removed the objects will not bounce back into the cavity. Also, prior traps have unduly complicated designs which substantially increase the cost of the mill construction and/or make it inconvenient to remove collected objects from the trap.

SUMMARY OF THE INVENTION The present invention is directed towards an improved tramp metal trap construction, which overcomes the dra backs and/or disadvantages of prior traps.

In accordance with the present invention, the improved trap is, supported on a door, which serves to define a portion of the mill cavity wall extending from the cavity inlet towards the cavity outlet in the direction of hammer rotation. The door may be opened to afford access to the cavity in order to facilitate repair or replacement of the impact hammers and cavity screen elements. The trap, which is arranged in communication with the mill cavity through an opening provided in the access door, generally includes a receiving chamber; a smoothly curved top wall plate portion extending from an upper edge of the trap opening for directing objects propelled therethrough downwardly into the receiving chamber; and a retaining plate portion extending from a lower edge of the trap opening and terminating in overlying relationship to the receiving chamber for retaining objects collected therein. The receiving chamber includes an access door through which collected objects may be removed.

By mounting the trap on the cavity access door, the construction of the trap is greatly simplified, and the trap is automatically moved to a relatively remote position, whenever the access door is opened, in order to permit access to the cavity unencumbered by the presence of the trap. Further, when the cavity access door is opened, the trap inlet opening is made accessible, thereby facilitating the withdrawal of objects, which may become wedged within the trap and otherwise difficult to remove through the receiving chamber access door.

DRAWINGS The nature and mode of operation of the present invention will now be more fully described in the following detailed description taken with the accompanying drawings wherein:

FIG. I is a perspective view of a hammer mill embodying the present invention with the mill cavity door in closed position;

FIG. 2 is a vertical sectional view taken through the mill of FIG. I; and

FIG. 3 is a fragmentary perspective view showing the mill cavity access door in open position.

DETAILED DESCRIPTION In the drawings, there is illustrated a hammer mill of a type having a casing 12, which serves to define a cavity 14 bounded by generally surfaces 16 and facing end wall surfaces defined by easing side plates 18, 19. Cavity 14 is provided with an upwardly opening inlet 20 and a downwardly opening outlet 22 formed by one or more screen elements 24.

As best shown in FIG. 2, a hammer device 26 is supported within cavity 14 by drive shaft 28 for rotation about a generally horizontally extending axis in a direction indicated by arrow 30. As will be apparent from viewing FIGS. 1 and 3, the respective ends of drive shaft 28 extend outwardly through casing side walls l8, l9 and are supported by suitable bearing devices 32, 33. Shaft 28 may be driven by any suitable means, such as an electric motor 34 connected to a drive shaft mounted pulley 36 by a drive belt 38.

While hammer device 26 may be of any suitable construction, it is shown for purposes of reference as including a hub portion 40, which is fixed for rotation with shaft 28, and a plurality of impact hammer elements 42, which are pivotally affixed to hub portion 40.

It will be understood that hammer mill 10, as thus far described, is of a conventional construction, but is modified in accordance with the preferred embodiment of the present invention by the provision of a tramp metal trap 50, which is supported by a mill cavity access door 52. Mill cavity access door 52 is shown as including side walls 54 and 55, which are connected by relatively upper and lower front walls 56 and 58, respectively, in order to form a unitary door construction. Access door 52 is supported for vertical pivotal movement between closed and open positions, shown respectively in FIGS. 1 and 3 by a bearing shaft 60 received within aligned openings provided in door side walls 54 and 55 and easing side walls 18 and 19. As will be apparent, the facing surfaces of side walls 54 and 55 are arranged substantially coplanar with those of side walls 18 and 19, and when door 52 is in its closed position any spacings or cracks between door side walls 54 and 55 and casing side walls 18 and 19 are sealed by door side wall weldments 62 and 63. Opening and closing of door 52 may be facilitated by mounting operating handle 64 on door side wall 55.

Referring particularly to FIG. 2, it will be seen that access door 52 is formed with a through opening 70, which is positioned in its cavity bounding wall and sized to receive objects propelled towards such wall by impact hammers 42 immediately upon introduction of such objects together with the material to be processed through cavity opening 20. Opening 70 would of course extend transversely of cavity 14 at least throughout the axial length of hammer device 26, and preferably between access door side walls 54 and 55 in order to facilitate construction of the access door.

Trap 50 is shown in the drawings as being of generally G- shaped cross sectional configuration such as to define a converging inlet or guide portion 72, which is arranged in communication with cavity opening 70, and a receiving chamber 74, which is arranged in communication with inlet portion 72 by a constricted passageway 76.

More specifically, trap 50 is defined by a pair of end walls and 81, which are fixed to and extend substantially coplanar with access door walls 54 and 55, respectively, a smoothly contoured top wall 84, which extends outwardly from adjacent an upper edge of opening 70 whereat it is arranged substantially tangent to that portion of the path of hammer rotation at which an object introduced into cavity 14 would nonnally be first engaged; a retaining plate 86, which extends outwardly from adjacent a lower edge of opening 70 and terminates in a downturned flange portion 860; a rear wall 90, which extends downwardly from plate 86; and a panel wall 92. Side walls 80 and 81 cooperate with top wall 84 and plate 86 to define inlet portion 72 with top wall 84 and flange portion 86a to define passageway 76 and with top wall 84, plate 86, flange portion 86a, rear wall 90 and panel wall 92 to define receiving chamber 74.

Panel wall 92, which is formed with upturned marginal edge portions 94 arranged to sealingly abut against downwardly terminating edge portions of side walls 80 and 81, top wall 84 and rear wall 90 is removably affixed to end walls 80 and 81 by suitably constructed quick release clamp devices 98 and 99 for the purpose of afiording access to articles collected in chamber 74.

By referring to FIG. 2, it will be understood that smoothly contoured top wall 84 serves to direct objects propelled through opening 70 downwardly into receiving chamber 74 through passageway 76, whether the object is propelled into initial engagement with the top wall or plate 86. Objects directed into receiving chamber 74 are thereafter positively prevented from bouncing back into inlet portion 72 and thus into cavity 14 by the constricted nature of passageways 76 and the generally rhomboidal shaped cross sectional configuration of receiving chamber 74. As indicated by arrow 100 in FIG. 2, the cross sectional configuration of receiving chamber 74 causes articles once directed thereinto, to move along or whirl about a path directed away from passageway 76, until they finally come to rest.

It will be understood that by mounting trap 50 on access door 52, the construction of the trap is greatly simplified and the trap is automatically moved to a relatively remote position, whenever the access door is opened, in order to permit access to cavity 14 unencumbered by the presence of the trap. Further, when access door 50 is opened, trap inlet opening 70 is made accessible, thereby facilitating the withdrawal of objects, such as long pieces of wire, which may become wedged within passageway 76 and thus be difficult to remove through receiving chamber 74.

lclaim:

1. In a hammer mill or the like having a cavity provided with upwardly opening material inlet and at least one downwardly opening material outlet, and impact hammer device supported within said cavity for rotation about a horizontal axis for processing material passing between said inlet and outlet, the improvement comprising:

a trap for removing foreign objects from said material to be processed immediately upon introduction thereof through said cavity inlet into engagement with said impact hammer device said trap being of a generally G- shaped configuration and defined by an inlet portion, a receiving chamber and a constricted passageway joining said inlet portion and said receiving chamber, said inlet portion being arranged in communication with said cavity through a cavity bounding wall opening positioned to receive objects propelled towards said bounding wall upon engagement with said impact hammer device, said inlet portion being vertically bounded by a smoothly contoured upper wall extending from adjacent an upper edge of said wall opening for directing objects propelled therethrough downwardly through said passageway into said receiving chamber and a retaining plate extending from adjacent a lower edge of said wall opening, said retaining plate additionally defining an upper bounding surface of said receiving chamber and cooperating with said upper wall to define said passageway, said receiving chamber being configured to direct objects introduced thereinto through said passageway to travel along a path directed away from said passageway, and said receiving chamber having a lower boundary surface defined by means movable to afford access to said receiving chamber. 2. A hammer mill for processing relatively soft materials and separating relatively hard foreign objects therefrom, said mill comprising in combination:

means defining a generally cylindrical cavity bounded by curved wall surfaces and spaced side wall surfaces, said curved wall surfaces bounding an upwardly opening cavity inlet for said material to be processed and at least one downwardly opening cavity outlet for processed material;

an impact hammer device for processing said material passing through said cavity between said inlet and outlet, said device being supported within said cavity for rotation substantially concentrically of said curved wall surfaces, a portion of said curved wall surfaces extending between said inlet and said outlet in the direction of device rotation defining a cavity opening, said cavity opening being positioned to receive said objects propelled towards said portion by said device upon introduction of said material and objects through said inlet into contact with said device; and

a trap having a generally G-shaped cross sectional configuration for collecting said objects passing through said cavity 0 enin said trap including a receiving chamber, a smooth y con oured upper wall extending from ad acent an upper edge of said cavity opening for directing objects propelled therethrough downwardly into said receiving chamber and a retaining plate extending from a lower edge of said cavity opening and terminating adjacent said upper wall, said upper wall and said retaining plate cooperating to define a trap inlet portion arranged in communication with said cavity opening and a constricted passageway for placing said inlet portion in communication with said receiving chamber.

3. A mill according to claim 2, wherein said receiving chamber is bounded in part by door means movable to afford access thereto.

4. A mill according to claim 3, wherein said portion is defined by a cavity access door, said trap being fixed to said access door.

5. A mill according to claim 2, wherein said portion of said curved wall surfaces is defined by a cavity access door, said trap is fixed to said access door, said receiving chamber is bounded in part by means movable to afford access thereto, and said receiving chamber is configured to direct objects introduced thereto through said passageway to travel along a path directed away from said passageway. 

1. In a hammer mill or the like having a cavity provided with upwardly opening material inlet and at least one downwardly opening material outlet, and impact hammer device supported within said cavity for rotation about a horizontal axis for processing material passing between said inlet and outlet, the improvement comprising: a trap for removing foreign objects from said material to be processed immediately upon introduction thereof through said cavity inlet into engagement with said impact hammer device said trap being of a generally G-shaped configuration and defined by an inlet portion, a receiving chamber and a constricted passageway joining said inlet portion and said receiving chamber, said inlet portion being arranged in communication with said cavity through a cavity bounding wall opening positioned to receive objects propelled towards said bounding wall upon engagement with said impact hammer device, said inlet portion being vertically bounded by a smoothly contoured upper wall extending from adjacent an upper edge of said wall opening for directing objects propelled therethrough downwardly through said passageway into said receiving chamber and a retaining plate extending from adjacent a lower edge of said wall opening, said retaining plate additionally defining an upper bounding surface of said receiving chamber and cooperating with said upper wall to define said passageway, said receiving chamber being configured to direct objects introduced thereinto through said passageway to travel along a path directed away from said passageway, and said receiving chamber having A lower boundary surface defined by means movable to afford access to said receiving chamber.
 2. A hammer mill for processing relatively soft materials and separating relatively hard foreign objects therefrom, said mill comprising in combination: means defining a generally cylindrical cavity bounded by curved wall surfaces and spaced side wall surfaces, said curved wall surfaces bounding an upwardly opening cavity inlet for said material to be processed and at least one downwardly opening cavity outlet for processed material; an impact hammer device for processing said material passing through said cavity between said inlet and outlet, said device being supported within said cavity for rotation substantially concentrically of said curved wall surfaces, a portion of said curved wall surfaces extending between said inlet and said outlet in the direction of device rotation defining a cavity opening, said cavity opening being positioned to receive said objects propelled towards said portion by said device upon introduction of said material and objects through said inlet into contact with said device; and a trap having a generally G-shaped cross sectional configuration for collecting said objects passing through said cavity opening, said trap including a receiving chamber, a smoothly contoured upper wall extending from adjacent an upper edge of said cavity opening for directing objects propelled therethrough downwardly into said receiving chamber and a retaining plate extending from a lower edge of said cavity opening and terminating adjacent said upper wall, said upper wall and said retaining plate cooperating to define a trap inlet portion arranged in communication with said cavity opening and a constricted passageway for placing said inlet portion in communication with said receiving chamber.
 3. A mill according to claim 2, wherein said receiving chamber is bounded in part by door means movable to afford access thereto.
 4. A mill according to claim 3, wherein said portion is defined by a cavity access door, said trap being fixed to said access door.
 5. A mill according to claim 2, wherein said portion of said curved wall surfaces is defined by a cavity access door, said trap is fixed to said access door, said receiving chamber is bounded in part by means movable to afford access thereto, and said receiving chamber is configured to direct objects introduced thereto through said passageway to travel along a path directed away from said passageway. 